Nursing Bottle Caries (BBTD) is a disease of infants that devastates the dentition of ethnic minority populations. In spite of the significant improvements made in the oral health during the past two decades, the decline in dental caries has not been uniform across all populations. In Puerto Rico, dental caries has been identified as an important health problem, specially in low socioeconomic groups. The major purpose of this study is to assess the concept that nursing bottle caries may be prevented by chemotherapeutic suppression of oral populations of mutans streptococci. The goals of this research are: 1) to test a chemotherapeutic intervention to suppress oral populations of mutans streptococci to prevent nursing bottle caries among Puerto Rican Infants, aged 12 months, and 2) to assess microbiological and behavioral risk factors. The specific intervention to be tested in this study is the professional application of a 10 percent povidone-iodine (Betadine). To assess risk, parent/caretakers will be interviewed concerning feeding practices and others and microbiological samples will be collected from infant subjects. The study will recruit a sample of 120 infant subjects who at their time of entry into the study are 12 months of age; sleep with a nursing bottle in their month that contains a cariogenic substrate; and harbor mutants streptococci in a pooled plaque sample obtained from their primary maxillary incisors and saliva. These infants will be randomized into two study groups. The Experimental Group will have a 10 percent Povidone-iodine solution topically applied to their teeth at 14, 16, 18, 20, and 22 months of age. The Control group infants will have a placebo solution applied in the same manner. On a bimonthly basis, during the course of the study period, the level of mutans streptococci in saliva sample and a pooled plaque sample from the maxillary incisors of each subject will be obtained and assessed. All infant subjects will be evaluated on a bimonthly basis during the course of the study period to determine the presence or absence of nursing bottle caries (decay and decalcification). Nursing bottle caries prevalence in the Experimental versus Control Groups, differences in mutans streptococcal levels in the Experimental versus Control Groups and the relationship of levels of mutans streptococci to the initiation of nursing caries are variables to be statistically analyzed. This research will broaden our view of preventive intervention strategies and the nursing bottle caries disease model.